The present invention relates generally to devices for delivering gases having a controlled vapor level and temperature to a delivery point, and more particularly to humidifier devices employing disposable humidifier cartridges which receive water from an adjacent container.
When a normally healthy person breathes atmospheric air, his air passages supply heated moisture to the inhaled gases, with the body being able to supply the required amount of heat and moisture. However, when subject to certain medical conditions, the patient's mechanism of supplying heated moisture is disrupted, and it becomes necessary to provide an artificial system for warming inspired gases to a point at or near normal body temperature before the gases are delivered to the patient. Accordingly, it is desirable to humidify the inspired gases to a level at or near full (100%) moisture saturation.
Conventional systems for providing heated and moisturized respiratory gases basically fall into two groups; nebulizers, which produce aerosols of fine water droplets, and heated humidifiers, which supply heat and moisture to a gas by the passage of the gas through or over a heated water bath or evaporated surface. The present invention is concerned with the heated humidifiers.
One such humidifier system includes a rigid, refillable water container designed to be placed upon a base unit having a heating element and is disclosed in U.S. Pat. No. 5,195,515 to Levine. This system includes a disposable heated cartridge humidifier for use with a collapsible water supply container and a heating device. The cartridge housing has a base plate fabricated from a conductive material such as metal, preferably aluminum. Included on the base plate is a peripheral lip which is crimped over a flange of a lower end of the housing.
One problem with this arrangement is the difficulty in controlling the inherent variation in the crimping action during assembly to prevent leakage between the housing and the base plate. Also, in the prior cartridge humidifier, the transfer of heat between the base plate and sidewall of the housing is a less than optimum arrangement for the humidification of the respiratory gases because heat from the base plate is laterally dissipated to the sidewalls of the housing and into the ambient air.
Another drawback of conventional heated cartridge humidifiers is that the incoming air is not given sufficient opportunity to be mixed with the water for full humidification, and thus is forced from the cartridge lacking adequate humidity.
Accordingly, it is the primary object of the present invention to provide an improved heated cartridge humidifier with a leak proof seal between the humidifier housing and the base plate.
It is another object of the present invention to provide an improved heated cartridge humidifier with a base plate which provides for improved heat conductivity from the heating element to the water in the cartridge.
It is a further object of the present invention to provide an improved heater cartridge humidifier in which incoming air is introduced into the cartridge in close proximity to the water supply to facilitate humidification of the air.
It is yet another object of the present invention to provide an improved heater cartridge humidifier which can be economically manufactured so as to be a disposable unit.